80 Headlights flashing issue

[nickc1]

I don't drive my car much at night but the past couple of times the headlights have randomly been flashing on and off for a couple of second intervals. This happens after about 10 minutes and whenever I'm driving along or at the lights. The brakes/accelerator don't seem to affect it.

This happened last night but went away after another 10 minutes or so. Other drivers think I'm flashing them which isn't ideal..

Anyone else experienced this in their C3 ?

[VetteMad]

Definiatly an electrical issue; might be easy to check.
I had a similar experience; however after a couple of night time driving the high beam just gave up and needed to be replaced.

Sorry can't be of help.

[sirfixalot]

The thermal o/load circuit breaker in headlite switch is operating due to current flow usually happens on high beam with 4 headlites on. Easiest fix  is to install a relay on high beam circuit. Secondary is fit relay on low beam also.Also aleviates any voltage drop problems on headlite circuit. In theory headlites should be brighter after installation

[nickc1]

Hard to install ? I'm not great when it comes to the electrical stuff.

It's happening on both low and high beam but I rarely drive with high beam anyway.

[bfit]

This does should like a thermal switch problem.
When you are having this problem, are you seeing any think on your amp meter.
are any other functions effected,
Do you have good earths on your lights.
Bfit

[sabre]

Not normal behavior for a thermal switch or overload problem. Normally the headlights will go out and only return after the bi-metal strip cools (10 sec - minutes) and the cycle will repeat depending on load so usually happens faster on hi beam. It's unlikely to have separate shorts in both hi and lo beam circuits so wiring from dip switch to lights is unlikely.
If it is an earth problem (quite possible) the front park lights will also be dimming as they use the same earth (assuming original wiring). 80's most common problem is the dip switch but that would rarely cause problems on both beams.
My money is on a bad earth in the headlight circuit.
Even if you find the problem, Sirfixalots suggestion of relays is a must. It will give better light and save your headlight and dip switches from failure.